The invention relates to a container for accommodating free-flowing products, in particular in the form of a beverage can, which is provided with a predetermined breaking line which, once broken open, produces a drinking or pouring opening. The beverage can is intended to be used particularly for carbonated beverages.
Beverage cans usually have a horseshoe-shaped predetermined breaking line which bounds a top or cover wall region of the can, on which a ring pull tab is fastened. If such a beverage can has been opened by virtue of the tab being actuated, it is no longer possible to close it effectively, which, in the case of carbonated drinks, results in the can contents having to be consumed rapidly or the drink otherwise going flat.
In order to cover the drinking or pouring opening it is already known from U.S. Pat. No. 3,726,432 to use an additional lid having a recessed opening and being formed as a rotary slider having a projecting tongue for breaking open the drinking and pouring opening. For doing so, the top wall of the container has a depression with a sloping surface which leads to the region of the later drinking and pouring opening. In this form of the top wall region bounded by the breaking line, it is not possible with the rotary slider to seal such drinking and pouring opening so that carbonated beverages will loose pressure quickly.
A container with a rotary lid closure of the applicants is known from German utility model DE U 200 04 152.5. It has proven difficult to seal carbonated beverages after breaking open the drinking and pouring opening.
Applicants of the present invention have described a beverage container with a rotary lid closure in WO 01/66431 A2 where the drinking and pouring opening will already be sealed after being opened. However, further amendments appear desirable when closing carbonated beverage containers once more.
These sealing difficulties are based on the top wall arching by the gas pressure of the carbonated beverage when the container is closed, this arching however being decreasing when the container is opened. In order to provide a good sealing effect, the rotary lid closure should follow the axial movement of the top wall, and engage the top wall with some pressure, when after breaking up the drinking and pouring opening, the rotary lid closure is being turned covering this drinking and pouring opening.
An object of the present invention is to provide a container with a rotary lid closure adapted to seal the drinking and pouring opening also in view of carbonated beverages.
With invention, the rotary lid closure is supported on the container on the one hand to initially break up the drinking and pouring opening when turning the rotary lid closure and then, on the other hand, to enable covering and sealing the opened drinking and pouring opening with wall portions of the rotary lid closure. The means for supporting the rotary lid closure include clip formations at the periphery of the rotary lid closure which co-operate with the edge seam between top wall and the rotationally symmetrical wall region of the container.
Furthermore, means for coupling the rotary lid closure to the container top wall are provided which are effective so that the rotary lid closure follows the container top wall when the same recedes somewhat in direction of the container interior due to decreasing inner pressure in the container. The coupling means are formed so as to allow rotary movement of the rotary lid closure relative to the container top wall. Generally, the rotary lid closure together with the coupling means is formed so as the usual stacking possibility of containers and tins one above the other remains preserved.
The coupling means of the rotary lid closure may include an additional central bearing and mounting point or place so as to hold the rotary lid closure closely at the container top wall in order to follow the arching movement up and down of the container top wall which in the case of carbonated beverages occur due to pressure variations.
The central bearing and mounting point or place of the rotary lid closure at the container top wall may comprise a pin-like extension of the container top wall and a hole recess in the rotary lid closure, furthermore latching means are provided to hold the members together. The latching means may include a cramp which may be placed upon the pin-like extension of the container top wall. As latching means also the latching engagement of dents into an annular depression on the pin-like extension can be used. Finally, it is also possible, after mounting the rotary lid closure, to form some kind of rivet head at the pin-like extension.
Additionally or alternatively to the central bearing and mounting point or place, the container top wall and the rotary lid closure may be provided with annular wall portions fitting to one another and defining screw surfaces or bayonet formations which become effective when turning the rotary lid closure so as to press the same onto the drinking and pouring opening, when in the position for covering the drinking and pouring opening, for better sealing purposes.
Finally, it is also possible to make the wall of the rotary closure with a different arching to that of the container top wall so that the rotary lid closure stays pressed onto the container top wall, also if after opening of the container, the container top wall recedes due to decreasing inner pressure in the container.